148 
8ELACHII. 
1876. Ptt/chodus latissimus, II. B. Geinitz, Palseontogr. vol. xx. pt. ii. 
p. 212, pi. xl. figs. 16-22. 
1878. Ptychodus latissimus, A. Fritsch, Kept. u. Fische bohm. Kreide- 
form. p. 15, ■woodcut fig. 30. 
1887. Ptychodus paiicisulcatus, A. S. Woodward, Quart. Journ. Geol. 
8oc. vol. xliii. p. 127, pi. x. fig. 12. 
Type. Detached teeth. 
Teeth very similar to those of P. polygyrus, but having the 
median transverse coronal ridges of enormous size, never completely 
reflexcd at the extremities. 
As proved by a specimen in the Brighton Museum, the lower 
median tooth of this species is very coarsely marked. The specimen 
figured by Agassiz, tom. cit. pi. xxv. a. fig. 8, must thus be regarded 
as the lower median tooth of P. polygyrus. 
Form. ^ Loc. Turonian and Senonian: S.E. England, Germany, 
Bohemia, and Russia. 
Except when otherwise stated, the following specimens were ob- 
tained from undetermined horizons in the Upper or Lower Chalk : — 
4358. Group of twelve naturally associated teeth, including two 
of upper median series, one of which is described and 
figured by the present writer, loe. cit . ; Lowes. 
Mantell Coll. 
4355, 4360, 4368. Group of ten naturally associated teeth, including 
one of lower median series, another of five, another of 
six teeth, and a smaller group of nine teeth ; Lewes. 
Mantell Coll. 
4369, 4371-2, 4374. Two large and two smaller teeth ; Lewes. 
Mantell Coll. 
P. 5396. Large tooth ; near Lewes. 
Presented by P. E. Coomhe, Esq., 1888. 
25826. Type specimen of Ptychodus paucisidcatus, Dixon ; Sussex. 
Dixon Coll. 
25826 a, 28335, 28346. Six teeth ; Southeram, Sussex. 
Dixon Coll. 
28341. Group of five small teeth; Lewes. 
28339. Eleven small teeth ; Lewes. 
49847. Four fragmentary teeth ; Lewes. 
P. 1394 a. Lower median tooth ; Sussex. 
Dixon Coll. 
Dixon Coll. 
Capron Coll. 
Egerfon Coll. 
